Smoking associated with similar risks for lung cancer in women compared with men

Takeaway

• In this meta-analysis involving more than 7 million participants, there was no evidence for a differential risk for smoking-related lung cancer in women vs men.
• However, there may yet be an unrealized sex difference in the risk for smoking-related lung cancer that would fully manifest as the smoking epidemic reaches full maturity in women.

Why this matters

• Previous analyses of a large UK primary care database showed that moderate and heavy smoking more strongly increased the lung cancer risk in women vs men.

Study design

• Meta-analysis evaluated 29 prospective cohort studies representing 99 cohorts, 7,113,303 individuals and 50,000 incident cases of lung cancer.
• Funding: None disclosed.

Key results

• In multiple adjusted model, current smoking was associated with increased risk for lung cancer in women (relative risk [RR], 6.99; 95% CI, 5.09-9.59) and men (RR, 7.33; 95% CI, 4.90-10.96).
• The corresponding ratio of RRs for lung cancer in women vs men was 0.92 (95% CI, 0.72-1.16).
• The women vs men ratio of RRs was 0.99 (95% CI, 0.65-1.52), 1.11 (95% CI, 0.75-1.64) and 0.94 (95% CI, 0.69-1.30) for <10, 10-20 and >20 cigarettes/day.

Limitations

• Heterogeneity across studies in study design, study population and other aspects.
• Detailed data on smoking behaviour and specific lung cancer subtypes not available.